U.S. patent application number 10/660595 was filed with the patent office on 2004-03-18 for image display system.
This patent application is currently assigned to FUJI PHOTO FILM CO., LTD.. Invention is credited to Hara, Shoji.
Application Number | 20040051710 10/660595 |
Document ID | / |
Family ID | 31986764 |
Filed Date | 2004-03-18 |
United States Patent
Application |
20040051710 |
Kind Code |
A1 |
Hara, Shoji |
March 18, 2004 |
Image display system
Abstract
An arbitrary cross section of an object is designated and a
depth perpendicular to the designated cross section is designated.
A cross-section projected-image data representing a cross-section
projected-image obtained by projecting, onto a plane parallel to
the designated cross section, averages of the pixel values arranged
in the directions of depth in the region defined by the designated
cross section and the designated depth including the designated
cross section is generated. Image processing conditions are set on
the basis of analysis of the cross-section projected-image data,
Image processing is carried out on the cross-section
projected-image data on the basis of the image processing
conditions and an image is displayed on the basis of the processed
cross-section projected-image data.
Inventors: |
Hara, Shoji; (Kanagawa-ken,
JP) |
Correspondence
Address: |
SUGHRUE MION, PLLC
2100 PENNSYLVANIA AVENUE, N.W.
SUITE 800
WASHINGTON
DC
20037
US
|
Assignee: |
FUJI PHOTO FILM CO., LTD.
|
Family ID: |
31986764 |
Appl. No.: |
10/660595 |
Filed: |
September 12, 2003 |
Current U.S.
Class: |
345/419 |
Current CPC
Class: |
G06T 19/00 20130101;
G06T 15/08 20130101; G06T 2219/008 20130101; G06T 2219/028
20130101; G06T 2200/24 20130101; G06T 2210/41 20130101 |
Class at
Publication: |
345/419 |
International
Class: |
G06T 015/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 13, 2002 |
JP |
268411/2002 |
Claims
What is claimed is:
1. An image display system comprising an image data obtaining means
which obtains image data consisting of three-dimensional pixel
values representing an object, a cross section designating means
for designating an arbitrary cross section of the object, a depth
designating means for designating a depth perpendicular to the
designated cross section, a cross-section projected-image data
generating means which generates, on the basis of the image data,
cross-section projected-image data representing a cross-section
projected-image obtained by projecting, onto a plane parallel to
the designated cross section, averages of the pixel values arranged
in the directions of depth in the region defined by the designated
cross section and the designated depth including the designated
cross section, an image processing condition setting means which
sets image processing conditions on the basis of the designated
depth, an image processing means which carries out image processing
on the cross-section projected-image data on the basis of the image
processing conditions set by the image processing condition setting
means, and a display means which displays an image on the basis of
the cross-section projected-image data processed by the image
processing means.
2. An image display system as defined in claim 1 in which said
image processing condition setting means sets the image processing
conditions on the basis of the kind of the object represented by
the image data.
3. An image display system as defined in claim 2 in which said
image processing condition setting means sets the image processing
conditions also on the basis of the purpose of observation of the
cross-section projected-image.
4. An image display system as defined in claim 3 in which the image
data is three-dimensional CT data.
5. An image display system as defined in claim 2 in which the image
data is three-dimensional CT data.
6. An image display system as defined in claim 1 in which said
image processing condition setting means sets the image processing
conditions on the basis of the purpose of observation of the
cross-section projected-image.
7. An image display system as defined in claim 6 in which the image
data is three-dimensional CT data.
8. An image display system as defined in claim 1 in which the image
data is three-dimensional CT data.
9. An image display system as defined in claim 1 in which the image
data represents a medical image.
10. An image display system as defined in claim 1 in which the
image processing includes at least one of gradation processing for
adjusting the density level or contrast of the image and frequency
processing for enhancing components in a particular frequency
band.
11. An image display system comprising an image data obtaining
means which obtains image data consisting of three-dimensional
pixel values representing an object, a cross section designating
means for designating an arbitrary cross section of the object, a
depth designating means for designating a depth perpendicular to
the designated cross section, a cross-section projected-image data
generating means which generates, on the basis of the image data,
cross-section projected-image data representing a cross-section
projected-image obtained by projecting, onto a plane parallel to
the designated cross section, averages of the pixel values arranged
in the directions of depth in the region defined by the designated
cross section and the designated depth including the designated
cross section, an image processing condition setting means which
sets image processing conditions on the basis of analysis of the
cross-section projected-image data, an image processing means which
carries out image processing on the cross-section projected-image
data on the basis of the image processing conditions set by the
image processing condition setting means, and a display means which
displays an image on the basis of the cross-section projected-image
data processed by the image processing means.
12. An image display system as defined in claim 11 in which said
image processing condition setting means sets the image processing
conditions on the basis of the kind of the object represented by
the image data.
13. An image display system as defined in claim 12 in which said
image processing condition setting means sets the image processing
conditions also on the basis of the purpose of observation of the
cross-section projected-image.
14. An image display system as defined in claim 13 in which the
image data is three-dimensional CT data.
15. An image display system as defined in claim 12 in which the
image data is three-dimensional CT data.
16. An image display system as defined in claim 11 in which said
image processing condition setting means sets the image processing
conditions on the basis of the purpose of observation of the
cross-section projected-image.
17. An image display system as defined in claim 16 in which the
image data is three-dimensional CT data.
18. An image display system as defined in claim 11 in which the
image data is three-dimensional CT data.
19. An image display system as defined in claim 11 in which the
image data represents a medical image.
20. An image display system as defined in claim 11 in which the
image processing includes at least one of gradation processing for
adjusting the density level or contrast of the image and frequency
processing for enhancing components in a particular frequency band.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to an image display system based on
three-dimensional image data, and more particularly to an image
display system which displays a tomogram along an arbitrary cross
section.
[0003] 2. Description of the Related Art
[0004] In order to observe the inside of an object, conventionally
a plurality of tomograms are taken at predetermined intervals along
an axis, for instance, by CT and are displayed. Recently, in order
to display the inside of an object to be more understandable, there
have been proposed a technology in which a plurality of pieces of
image data (obtained, for instance, by CT) representing a plurality
of cross sections are superimposed to obtain image data of a
three-dimensional region of the object, and a tomogram of the
object sectioned along a cross-section passing through a
predetermined axis is displayed on the basis of the image data of
the three-dimensional region of the object (see, for instance, U.S.
Laid-Open No. 20020015006, or a technology in which a tomogram of
the object sectioned along an arbitrary cross section (see, for
instance, Japanese Unexamined Patent Publication No.
10(1998)-137236). Further, there has been proposed a technology in
which a plurality of pieces of image data are subjected to weighted
average processing and a weighted-average tomogram, in other words,
"a tomogram provided with a depth" is displayed. (See, for
instance, Japanese Unexamined Patent Publication No.
9(1997)-238934.)
[0005] According to these technologies, the user can easily grasp a
three-dimensional image of the inside of an object since a tomogram
along an arbitrary cross section of the object can be displayed and
at the same time, the tomogram includes, as well as information on
the designated cross section, information on cross sections before
and behind the designated cross section.
[0006] In accordance with such a technology of displaying a
tomogram having depth, the density information of the image to be
displayed generally varies depending on the region to be displayed
as an image. Accordingly, when the cross section and/or the depth
of the tomogram to be displayed are changed, there is sometimes
displayed a tomogram which is low in density and/or contrast and is
hard to observe. Such a tomogram generally requires image
processing in order to make it observable. Conventionally, the
image processing has been manually carried out by the user. That
is, each time the cross section and/or the depth of the tomogram to
be displayed are changed and a tomogram hard to observe is
displayed, it is necessary for the user to set image processing
conditions and carry out image processing on the tomogram under the
image processing conditions. However, these operations are
troublesome for the user and make it infeasible to efficiently
observe tomograms.
SUMMARY OF THE INVENTION
[0007] In view of the foregoing observations and description, the
primary object of the present invention is to provide an image
display system which does not require the user's troublesome
operation for image processing and makes it feasible to efficiently
observe tomograms of an object.
[0008] In accordance with a first aspect of the present invention,
there is provided an image display system comprising an image data
obtaining means which obtains image data consisting of
three-dimensional pixel values representing an object, a cross
section designating means for designating an arbitrary cross
section of the object, a depth designating means for designating a
depth perpendicular to the designated cross section, a
cross-section projected-image data generating means which
generates, on the basis of the image data, cross-section
projected-image data representing a cross-section projected-image
obtained by projecting, onto a plane parallel to the designated
cross section, averages of the pixel values arranged in the
directions of depth in the region defined by the designated cross
section and the designated depth including the designated cross
section, an image processing condition setting means which sets
image processing conditions on the basis of the designated depth,
an image processing means which carries out image processing on the
cross-section projected-image data on the basis of the image
processing conditions set by the image processing condition setting
means, and a display means which displays an image on the basis of
the cross-section projected-image data processed by the image
processing means.
[0009] In accordance with a second aspect of the present invention,
there is provided an image display system comprising an image data
obtaining means which obtains image data consisting of
three-dimensional pixel values representing an object, a cross
section designating means for designating an arbitrary cross
section of the object, a depth designating means for designating a
depth perpendicular to the designated cross section, a
cross-section projected-image data generating means which
generates, on the basis of the image data, cross-section
projected-image data representing a cross-section projected-image
obtained by projecting, onto a plane parallel to the designated
cross section, averages of the pixel values arranged in the
directions of depth in the region defined by the designated cross
section and the designated depth including the designated cross
section, an image processing condition setting means which sets
image processing conditions on the basis of analysis of the
cross-section projected-image data, an image processing means which
carries out image processing on the cross-section projected-image
data on the basis of the image processing conditions set by the
image processing condition setting means, and a display means which
displays an image on the basis of the cross-section projected-image
data processed by the image processing means.
[0010] The image display system in accordance with the second
aspect of the present invention differs from that in accordance
with the first aspect of the present invention in that the image
processing conditions are set on the basis of the designated depth
in the image display system in accordance with the first aspect of
the present invention whereas the image processing conditions are
set on the basis of analysis of the cross-section projected-image
data in the image display system in accordance with the second
aspect of the present invention.
[0011] The term "image data consisting of three-dimensional pixel
values representing an object" as used here means data expressing
the internal structure of an object by values of a plurality of
three-dimensionally arranged pixels, and may be, for instance,
three-dimensional data obtained by superimposing a plurality of
two-dimensionally arranged pixel values representing a plurality of
tomograms taken at predetermined intervals along an axis, for
instance, by CT, along the axis.
[0012] The term "the region defined by the designated cross section
and the designated depth including the designated cross section" as
used here means a region which is between a pair of planes apart
from each other at a distance of the designated depth in parallel
to the designated cross-section and includes the designated cross
section.
[0013] Further, the "image processing" may include, for instance,
gradation processing for adjusting the density level and/or the
contrast of the image or frequency processing for enhancing
components in a particular frequency band.
[0014] Further, the "analysis of the cross-section projected-image
data" as used here means, for instance, a histogram analysis
carried out on pixel values of the cross-section projected-image
data.
[0015] The "depth designating means" may be one which can designate
an arbitrary depth or one which selects one of options.
[0016] In the image display system in accordance with the first
aspect of the present invention, the image processing condition
setting means may set the image processing conditions on the basis
of the designated depth either by reading out image processing
conditions prepared in advance by the value of the designated
depth, or by calculating the image processing conditions on the
basis of each designated depth.
[0017] In the image display system of the present invention (in
accordance with the first and second aspects of the present
invention), the image processing condition setting means may set
the image processing conditions either according to the kind of the
object represented by the image data or according to the purpose of
observation of the cross-section projected-image.
[0018] The "image data obtaining means" may obtain the image data
either by reading out the image data from a storage means provided
in the image display system of the present invention or by reading
out the image data from a CT, an image server or the like connected
to the image display system of the present invention by way of, for
instance, a network.
[0019] The "image data" may be three-dimensional CT data.
[0020] Further, the "image data" may be image data representing a
medical image obtained by taking an affected part of an organism
such as a human or an animal.
[0021] In the image display system of the present invention, since
the image processing conditions are set in response to change of
the cross section and/or the depth, troublesome operations by the
user including setting of the image processing conditions and image
processing become unnecessary, whereby efficient observation of
images can be realized.
[0022] When the image processing conditions are set according to
the kind of the object represented by the image data, the image
processing conditions can be set according to the feature in
density by the kind of the object, whereby more observable image
can be displayed.
[0023] Further when the image processing conditions are set
according to the purpose of observation, the image processing
conditions can be set to be suitable for the purpose of
observation, whereby more observable image can be displayed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 is a schematic block diagram showing an image display
system in accordance with an embodiment of the present
invention,
[0025] FIG. 2 is a perspective view showing an appearance of the
image display system,
[0026] FIG. 3 is a view showing the screen of the image display
system in the Tile View mode just after the image display system is
started,
[0027] FIG. 4 is a view showing the screen of the image display
system in the Tile View mode where one cross-section
projected-image is displayed,
[0028] FIG. 5 is a view showing the screen of the image display
system in the Tile View mode where nine cross-section
projected-images are displayed,
[0029] FIG. 6 is a view showing the screen of the image display
system when the view mode is switched to the Mpr View mode,
[0030] FIG. 7 is a view showing the screen of the image display
system where a cross-section projected-image as seen from an
intermediate position between the front and the right side of the
object is displayed in the window Wo, and
[0031] FIG. 8 is a view showing the screen of the image display
system where a cross-section projected-image as seen from an
intermediate position between the front and the bottom of the
object is displayed in the window Wo.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0032] In FIGS. 1 and 2, an image display system 1 in accordance
with an embodiment of the present invention comprises an image data
obtaining means 10 which obtains image data V consisting of
three-dimensional pixel values representing an object, a cross
section designating means 20 for designating an arbitrary cross
section R of the object, a depth designating means 30 for
designating a depth T perpendicular to the designated cross section
R, a cross-section projected-image data generating means 40 which
generates, on the basis of the image data V, cross-section
projected-image data P representing a cross-section projected-image
P (an image and image data representing the image will be denoted
by the same symbol for the purpose of simplicity) obtained by
projecting, onto a plane parallel to the designated cross section
R, averages of the pixel values arranged in the directions of depth
in the region defined by the designated cross section R and the
designated depth T including the designated cross section R, an
image processing condition setting means 50 which sets image
processing conditions on the basis of analysis of the cross-section
projected-image data, an image processing means 60 which obtains
processed cross-section projected-image data P' by carrying out
image processing on the cross-section projected-image data P on the
basis of the image processing conditions set by the image
processing condition setting means 50, and a display means 70 which
displays an image on the basis of the processed cross-section
projected-image data P'.
[0033] The image processing means 70 comprises a display control
section 71 which converts the processed cross-section
projected-image data P' into an image signal for display and causes
an image display section 72 to display an image on the basis of the
image signal. The image display section 72 may comprise, for
instance, a CRT panel or a liquid crystal panel.
[0034] The image display system 1 further comprises an input means
90 comprising a keyboard 91, a mouse 92 and the like for inputting
data for designating a cross section R and the depth T, and for
various controls.
[0035] As shown in FIG. 2, the image display section 72 and the
input means 90 are disposed on a table 2 whereas the image data
obtaining means 10, the cross-section projected-image data
generating means 40 and the like are built in a body 3 disposed
below the table 2.
[0036] The image data obtaining means 10 comprises, for instance, a
magnetic recording system such as a hard disc which reads out image
data V from a computer-readable portable recording medium such as a
CD-ROM or an MO (magneto optical disc) or from a CT connected to
the image display system 1 by way of a network or the like and
stores the image data V.
[0037] The cross section designating means 20 is for designating a
cross section R of the object and the depth designating means 30 is
for designating a depth T including the designated cross section R.
The region defined by the designated cross section R and the
designated depth T is displayed as the cross-section
projected-image P. Only one cross section R may be designated or a
plurality of cross sections R arranged at predetermined intervals
along an axis may be designated. Designation of the cross section R
and the depth T may be effected either by displaying an image
representing the object on the screen of the image display section
72 and pointing points which particularize a cross section R on the
image with the keyboard 91 and/or the mouse 92, or by displaying an
image which is a model of a cross section R and determining a
desired position of a cross section R by three-dimensionally moving
or rotating the image along or about an axis, or by directly
inputting values of coordinates representing points which
particularize a cross section R or values representing a depth
T.
[0038] The cross-section projected-image data generating means 40
averages values of pixels in the region defined by the designated
cross section R and the designated depth T including the designated
cross section R in the direction of depth and projects the averages
of the pixel values onto a plane parallel to the designated cross
section R, thereby generating two-dimensional cross-section
projected-image data P representing the cross-section
projected-image P. The cross-section projected-image data
generating means 40 generates cross-section projected-image data P
not only for the region defined by the designated cross section R
and the designated depth T including the designated cross section R
but also for regions defined by cross sections and depths which are
preset or selectable from those in predetermined ranges. For
example, when the image display system is started, the
cross-section projected-image data generating means 40 sometimes
generates cross-section projected-image data P for a region
particularized in accordance with preset initial conditions and
sometimes generates cross-section projected-image data P for a
region particularized by designating cross sections perpendicular
to a predetermined axis. When the designated depth T is
substantially equal to the thickness of the object, the
cross-section projected-image data P reflects averages of the
values of substantially all the pixels inside the object and
accordingly, the image represented by the cross-section
projected-image data P is substantially the same as an ordinary
radiation image. That is, by selecting the depth T, the
cross-section projected-image P can be displayed in a form suitable
for the intended application.
[0039] The image processing condition setting means 50 sets the
image processing conditions on the basis of analysis of the
cross-section projected-image data P, and the image processing
means 60 obtains processed cross-section projected-image data P' by
carrying out image processing such as gradation processing or
frequency processing on the cross-section projected-image data P on
the basis of the image processing conditions set by the image
processing condition setting means 50.
[0040] Depending on the region of the object to be displayed as the
cross-section projected-image P, various pieces of density
information are included in the image, which makes the image
unobservable. However, when the image processing conditions are set
on the basis of analysis of the cross-section projected-image data
P and image processing is carried out on the cross-section
projected-image data P on the basis of the image processing
conditions thus set, such a cross-section projected-image P can be
converted to a more observable image. Especially, when the depth T
is set to be relatively large, the image tends to be an image in
which the density changes relatively gently due to averaging of the
pixel values. In such a case, in order to make the image more
observable, frequency processing in which frequency components are
differently weighted so that edges of the image are enhanced may be
carried out on the cross-section projected-image data P. The
analysis of the cross-section projected-image data P may be, for
instance, a histogram analysis of pixel values.
[0041] As the method of setting the gradation processing
conditions, there has been well known a method in which to which
ranges of pixel values the full scale of the gradation level
representing the density of the image is to be applied is set on
the basis of the window value WC (the center value of the range of
the pixel values) and the window width WW (the width of the range
of the pixel values), and in this embodiment, the gradation
processing conditions are set in this method.
[0042] The display control section 71 sets the layout of the screen
of the image display section 72 so that a cross-sectional image
display area in which one or more cross-section projected-image is
displayed and a control panel display area in which a control panel
for various settings are set side by side. Further, the display
control section 71 can switch the view mode between two different
view modes. One view mode is "Tile View" mode in which a plurality
of continuous cross-section projected-images taken along cross
sections at predetermined intervals along an axis are displayed at
one time side by side. The other view mode is "Mpr View" mode in
which three cross-section projected-images respectively taken along
cross sections perpendicular to three predetermined axes which are
perpendicular to each other and a cross-section projected-image
taken along a cross designated section are displayed at one time
side by side. The Tile View mode and the Mpr View mode are switched
in response to a control of the user. The three predetermined axes
which are perpendicular to each other are A axis extending in the
vertical direction of the object, C (coronal) axis extending
forward of the object, and S (sagittal) axis extending in the
transverse direction of the object.
[0043] Operation of the image display system of this embodiment
will be described hereinbelow.
[0044] In this embodiment, it is assumed that the image data V is
three-dimensional data obtained by superimposing a plurality of
pieces of image data taken by a CT in the direction of axis of
slice, and the three-dimensional image data V has been input into
the image data obtaining means 10 and has been stored therein.
[0045] When the image display system 1 of this embodiment is
started, the display control section 71 causes the image display
section 72 to display in predetermined one of the Tile View mode
and the Mpr View mode. In this embodiment, the display control
section 71 causes the image display section 72 to display in the
Tile View mode upon start-up of the image display system 1.
[0046] FIG. 3 shows the layout of the screen of the image display
section 72 just after the image display system 1 is started. The
control panel display area appears on the right side of the screen
and is indicated at X and the cross-sectional image display area
appear on the left side of the screen and is indicated at Y.
[0047] Functions of control buttons and the like in the control
panel display area X will be described, hereinbelow.
[0048] "START" button X1 is for starting display of cross-section
projected-images. When the START button X1 is pushed, cross-section
projected-images are displayed in the cross-sectional image display
area Y on the basis of three-dimensional data stored in the image
data obtaining means 10 according to settings which have been
registered in advance.
[0049] "Config." button X2 is for registering various settings. A
setting display window is displayed in response to depression of
the Config. button X2 and selection of the mode upon start-up of
the image display system 1, presetting of gradation processing
conditions and the like can be performed.
[0050] "View Mode" area X3 is for switching the view modes between
the "Tile View" mode and the "Mpr View" mode.
[0051] "Windowing" area X4 is for setting gradation processing
conditions. Gradation conditions can be selected from the dropdown
menu in "Preset" in which a plurality of patterns of gradation
processing conditions corresponding to preset combinations of the
window value WC and the window width WW. When no gradation
processing condition has been preset or no gradation processing
condition has been selected, the default gradation processing
conditions are applied. The set window width and window value are
displayed like "WW:1600" and "WC:-600". When the gradation
processing conditions are to be adjusted, a gradation setting
button is pushed. When the gradation setting button is pushed, the
window width WW and the window value WC become variable. When the
mouse 92 is moved up and down and left and right with its click
button depressed, the window width WW and the window value WC are
continuously vary and the values of the window width WW and the
window value WC are fixed at the values at the time when the mouse
92 is stopped and its click button is released. When the gradation
setting button is pushed again, the window width WW and the window
value WC become invariable. When "Reset" button is pushed, the
window width WW and the window value WC are reset to the values
corresponding to the gradation processing conditions set in
"Preset". When no gradation processing condition is set in
"Preset", the gradation processing conditions are reset to the
default. When "Auto" button is depressed to turn on an automatic
setting function, histogram analysis is automatically carried out
on the pixel values of the image to be displayed and proper
gradation processing conditions are constantly set on the basis of
the analysis.
[0052] "Pan" area X5 is for decreasing the reduction ratio. While
button P is kept depressed, the reduction ratio is kept decreased
at a constant rate so that the image varies to cover larger area of
the object. In response to depression of a button R, the reduction
ratio is reset to the original value.
[0053] "Zoom" area X6 is for increasing the reduction ratio. While
button Z is kept depressed, the reduction ratio is kept increased
at a constant rate so that the image is gradually enlarged. In
response to depression of a button R, the reduction ratio is reset
to the original value.
[0054] "CT Value" area X7 is for recognizing the value of each
pixel (CT value). When button C is depressed, the function of
displaying the CT value is turned ON. The CT value of the pixel
pointed by the pointer is displayed beside the C button. When
button C is depressed again, the function of displaying the CT
value is turned OFF.
[0055] "Overlay" area X8 is for selecting whether an additional
line is to be displayed in the image. When button O is depressed,
the function of displaying an additional line is turned ON, and
additional lines such as centerline and/or a line indicating the
cross section R are displayed. When button O is depressed again,
the additional line displaying function is turned OFF and the
additional lines disappear.
[0056] "Spacing" area X9 is displayed only in Tile View mode, and
is for setting the space between cross-section projected-images
when a plurality of cross-section projected-images continuous in
the direction of an axis (A axis, C axis and S axis) are to be
displayed. The space between cross-section projected-images can be
changed by pushing an arrow button and the space between
cross-section projected-images is shown beside the arrow
buttons.
[0057] "Thickness" button X10 is for designating the depth T, and a
selection screen is displayed in response to depression of
Thickness button so that a desired depth can be selected from
options in the selection screen. The depth T may be set by directly
inputting a value or by moving a slider in place of selecting from
the options.
[0058] "Tile" area X11 is displayed only in Tile View mode, and is
for setting the number of images to be displayed in the
cross-sectional image display area Y at one time. The number of
images to be displayed in the cross-sectional image display area Y
at one time is selected, for instance, from 1.times.1 (one),
2.times.2 (four), 3.times.3 (nine) and 4.times.4 (sixteen) though
need not be limited to these values.
[0059] The typical image display area indicated at X12 is an area
where typical three cross-sectional images respectively taken along
cross sections perpendicular to the A axis, C axis and S axis and
passing through the center of the object. When one of the three
cross-sectional images is designated, continuous cross-section
projected-images taken in the same direction as the designated
cross-section image are displayed in the cross-sectional image
display area Y in a number set in Tile area X11.
[0060] Slide bar X13 is for setting the region of the object to be
displayed as a cross-section projected-image. When the slide bar is
moved up and down, the region of the object to be displayed is
shifted along the direction of axis of the designated cross section
with the width in the direction of axis kept unchanged. The region
currently displayed is shown by two lines (L1 and L2) representing
the ends of the image in the three cross-sectional images displayed
in the typical image display area X12. In place of using the slide
bar X13, the region of the object to be displayed may be shifted by
dragging the two lines representing the ends of the image in the
three cross-sectional images displayed in the typical image display
area X12 by the use of the mouse 92.
[0061] When the START button X1 is depressed after the image
display system 1 is started, the cross-section projected-image data
generating means 40 reads out necessary data from the image data
obtaining means 40 according to the conditions set in the control
panel display area X and generates cross-section projected-image
data Pt representing a cross-section projected-image Pt to be
displayed in Tile View mode. Here, it is assumed that the
conditions have been set as follows. "Tile" X11=1.times.1, the
typical image display area X12=Dc, the cross section R selected by
the slide bar X13=a section including the center of the chest:
default, the depth T selected in Thickness area X10=1 mm: default.
Further it is assumed that the gradation condition automatic
setting function has been turned on by "Auto" button in Windowing
area X4 so that the image processing condition setting means 50
sets the image processing conditions on the basis of a histogram
analysis of the CT values of the cross-section projected-image data
P. For example, the image processing condition setting means 50
sets gradation conditions so that the image data P is converted so
that the range of the CT values of an important part of the overall
image corresponds to the dynamic range of gradation. The image
processing means 60 obtains processed cross-section projected-image
data P' by carrying out image processing on the cross-section
projected-image data P on the basis of the image processing
conditions set by the image processing condition setting means 50.
The display control section 71 causes the image display section 72
to display a cross-section projected-image P' (i.e., a
cross-section projected-image of the chest as seen from front) in
the cross-sectional image display area Y on the screen thereof on
the basis of the processed cross-section projected-image data
P'.
[0062] If "Tile" is changed to 3.times.3, nine cross-section
projected-images are displayed at spaces set in "Spacing". These
images reflect all the conditions set in the control panel display
area X.
[0063] FIG. 5 is a view showing the screen of the image display
system in the Tile View mode where nine cross-section
projected-images P' are displayed.
[0064] When the view mode is switched to the "Mpr View" mode, four
windows are displayed at one time in the cross-sectional image
display area Y, and control sections different from X10 to X13
shown in FIG. 3 are displayed in the control panel display area
X.
[0065] FIG. 6 is a view showing the screen of the image display
system 1 when the view mode is switched to the Mpr View mode. In
the upper left window Wa, a cross-section projected-image Pa as
seen from below taken along a section perpendicular to A-axis is
displayed, in the lower left window Wc, a cross-section
projected-image Pc as seen from front taken along a section
perpendicular to C-axis is displayed, in the lower right window Ws,
a cross-section projected-image Ps as seen from left taken along a
section perpendicular to S-axis is displayed, and in the upper
right window Wo, a cross-section projected-image Po taken along an
arbitrary section is displayed.
[0066] Also in the Mpr View mode, a series of processing, necessary
data is read out from image data obtaining means 40 and
cross-section projected-image data P is generated by the
cross-section projected-image data generating means 50, image
processing conditions are set by the image processing condition
setting means 50 on the basis of a histogram analysis of the CT
values of the cross-section projected-image data P, processed
cross-section projected-image data P' is obtained by carrying out
image processing on the cross-section projected-image data P on the
basis of the image processing conditions set by the image
processing condition setting means 50 and a cross-section
projected-image P' is displayed on the screen of the image display
section 72 are executed upon designation of the cross section R and
the depth T as in the Tile View mode.
[0067] Immediately after the view mode is switched, cross-section
projected-images respectively taken along cross sections
perpendicular to the axes and passing through the center of the
object are displayed in windows Wa, Wc and Ws, and an image which
has been viewed in the Tile View mode is displayed in the window
Wo. In order for a cross-section projected-image Po taken along an
arbitrary section to be displayed, the Section Ro is designated by
copying one of the cross-section projected-images Pa, Pc and Ps
(These cross-section projected-images will be referred to as
"three-axes cross-section projected-images", hereinbelow.)
displayed in the windows Wa, Wc and Ws to the window Wo, rotating
the copied image about one of A-axis, C-axis and S-axis, thereby
determining the axis perpendicular to the section Ro of the copied
image, and moving the section Ro of the copied image along the
axis, and designating the depth To.
[0068] Function of the different control button and the like in the
control panel display area X will be described, hereinbelow.
[0069] "Copy From" area X15 is for copying one of the three-axes
cross-section projected-images and when one of "A", "C" and "S"
button is depressed, the cross-section projected-image displayed in
the corresponding one of the windows Pa, Pc and Ps is copied to the
window Wo. Copy of the image can also be executed by dragging a
desired image and dropping it in the window Wo.
[0070] "Rotate" area X14 is for rotating the section Ro of the
cross-section projected-image Po displayed in the window Wo about
one of the A-axis, C-axis and S-axis, and when one of the arrow
buttons is depressed, the section Ro of the cross-section
projected-image Po is rotated toward the depressed arrow button.
Rotation of the section Ro can also be executed by dragging a line
(to be described later) displayed in each of the three-axes
cross-section projected-images to represent the position of the
section to rotate the line by the mouse 92.
[0071] Slide Bar X17 is for moving the section of the selected
cross-section projected-images of those displayed in the respective
windows in the direction of axis perpendicular to the section. By
moving Slide Bar X17, the section is moved and the image displayed
changes. By depressing arrows on the upper and lower sides of Slide
Bar X17, the section also can be moved. The cross-section
projected-image can be selected by clicking the cross-section
projected-image with the mouse 92. The outer edge of the selected
cross-section projected-image is colored in a remarkable color such
as red.
[0072] "Expand" button X16 is for enlarging the cross-section
projected-image Po displayed in the window Wo. When Expand button
X16 is depressed, the cross-section projected-image Po displayed in
the window Wo is displayed in an enlarged scale over the entire
area of the cross-sectional image display area Y.
[0073] "Thickness" area X18 is for designating the depth T of the
respective cross-section projected-images displayed in the windows
Wa, Wc, Ws and Wo. When one of "A", "C", "S" and "O" buttons are
depressed, the depth T of the corresponding cross-section
projected-image Pa, Pc, Ps or Po can be designated.
[0074] An example of control for displaying a cross-section
projected-image Po along an arbitrary section will be described,
hereinbelow, in conjunction with a case where a cross-section
projected-image as seen from an intermediate position between the
front and the right side of the object is displayed as the
cross-section projected-image Po.
[0075] One of the three axes cross-section projected-images which
is the most suitable for designating a desired section is copied to
the window Wo. It is assumed here that the most suitable one of the
three axes cross-section projected-images is the cross-section
projected-image Pc displayed in the window Wc. "C" button in the
Copy From area X15 is depressed to copy the cross-section
projected-image Pc to the window Wo. Then the leftward arrow button
in the Rotate area X14 is repeatedly depressed to rotate the
section Ro about A-axis in the counterclockwise direction as seen
from below to a desired angle. Thereafter, the section Ro is moved
along the axis perpendicular to the section Ro to a desired
position by sliding the slide bar X17 or by depressing one of the
arrow buttons associated with the slide bar X17. The depth To is
designated by depressing O button in Thickness area and selecting a
desired depth.
[0076] FIG. 7 is a view showing the screen of the image display
system where a cross-section projected-image Po as seen from an
intermediate position between the front and the right side of the
object is displayed in the window Wo, and FIG. 8 is a view showing
the screen of the image display system where a cross-section
projected-image Po as seen from an intermediate position between
the front and the bottom of the object is displayed in the window
Wo. The section Ro may be rotated about a plurality of axes without
limited to only one axis.
[0077] Where the section of each of the cross-section
projected-images is positioned in the three-dimensional space is
shown by lines displayed in the respective images. That is, lines
M1 to M4 displayed in the cross-section projected-images Pa, Pc and
Ps mutually show the positions of sections Ra, Rc and Rs in the
cross-section projected-images Pa, Pc and Ps. That is, the line Ml
is an intersection of the section Ra and the section Rs, the line
M2 is an intersection of the section Ra and the section Rc, the
line M3 is an intersection of the section Rc and the section Ra,
and the line M4 is an intersection of the section Rs and the
section Ra. Further, lines M5 to M7 displayed in the cross-section
projected-images Pa, Pc and Ps show the position of section Ro in
the cross-section projected-images Po. That is, the line M5 is an
intersection of the section Ra and the section Ro, the line M6 is
an intersection of the section Rc and the section Ro and the line
M7 is an intersection of the section Rs and the section Ro.
Otherwise the position of the section may be displayed in a solid
model figure of the object displayed beside the cross-section
projected-image.
[0078] The view mode can be switched from the Tile View mode to the
Mpr View mode in various methods other than designating the view
mode in the View Mode area. For example, when there is an
interested image in the cross-section projected-images displayed in
the Tile View mode, the view mode is switched to the Mpr View mode,
for instance, by double-clicking the mouse 92 on a point on the
interested image and cross-section projected-images where said
three axes pass through the point are displayed in the windows Wa,
Wc and Ws.
[0079] Various settings may be arranged to be reflected upon
switching of the view mode, to be able to be set independently, or
to be able to select by items whether the setting is to be
reflected. It is possible to arrange the settings to be stored in a
plurality of patterns so that the patterns may be switched as
desired. Further, it is possible to arrange the settings to be
stored so that work can be smoothly continued when the view mode is
returned to the original view mode.
[0080] As can be understood from the description above, in the
image display system 1 of this embodiment, since image data V
consisting of three-dimensional pixel values representing an object
is obtained, an arbitrary cross section R of the object and a depth
T perpendicular to the cross section R are designated,
cross-section projected-image data P representing a cross-section
projected-image obtained by projecting, onto a plane parallel to
the designated cross section, averages of the pixel values arranged
in the directions of depth in the region defined by the designated
cross section and the designated depth including the designated
cross section is generated on the basis of the obtained image data
V, image processing conditions are set on the basis of analysis of
the generated cross-section projected-image data P, image
processing is carried out on the cross-section projected-image data
P on the basis of the image processing conditions set to obtain
processed cross-section projected-image data P', and an image is
displayed on the basis of the processed cross-section
projected-image data P', an observable image is displayed in
response to switching of the cross section R and/or the depth T and
troublesome operations by the user including setting of the image
processing conditions and image processing become unnecessary,
whereby efficient observation of images can be realized.
[0081] Though, in the image display system 1 of this embodiment,
the image processing condition setting means 50 sets image
processing conditions on the basis of "analysis of the
cross-section projected-image data P", the image processing
condition setting means may set image processing conditions on the
basis of the "depth designated by the depth designating means 20".
Generally, the image density tends to be leveled and the image
tends to be lower in contrast as the depth increases. Accordingly,
it is preferred that the image processing conditions be changed
even if only the depth is changed. For example, the image
processing conditions (gradation processing conditions) are set so
that the width of the range of the CT values allotted to the
dynamic range of gradation is gradually narrowed about the average
of the CT values as the depth increases.
[0082] Also in the case where image processing conditions are set
on the basis of the "depth designated by the depth designating
means 20", an observable image is displayed in response to
switching of the depth T and troublesome operations by the user
including setting of the image processing conditions and image
processing become unnecessary, whereby efficient observation of
images can be realized, as in the case where image processing
conditions are set on the basis of "analysis of the cross-section
projected-image data P".
[0083] Further, the image processing by the image processing means
50 need not be limited to gradation processing or frequency
processing described above. For example, the pixels whose CT values
exceed a predetermined threshold value may be displayed in a
different color or different colors according to the CT values.
[0084] Though, in the embodiment described above, cross-section
projected-image data P is generated by projecting, onto a plane
parallel to the designated cross section, averages of the pixel
values arranged in the directions of depth in the region defined by
the designated cross section and the designated depth including the
designated cross section, values other than the simple averages of
the pixel values arranged in the directions of depth may be used.
For example, weighted averages weighted according to the pixel
values, or medians maybe used. Further, even a maximum value (MIP)
or a minimum value (MinIP) may be used.
[0085] Further, the image processing condition setting means 50 may
set the image processing conditions taking into account the kind of
the object, the purpose of observation and/or the like input
through the input means 90 in addition to the depth or the analysis
of the cross-section projected-image data. For example, when the
kind of the object is a human chest, the difference in the pixel
value between the lung and the mediastinum is generally large and
the image of the chest tends to be high in contrast. In such a
case, gradation processing conditions are set so that an image
relatively low in contrast is obtained. Whereas when the purpose of
observation is to measure the cardiothoracic ratio, the image
processing conditions may be gradation processing conditions which
enhances high-frequency components so that edges of the heart and
the thorax are clearly displayed. With such an arrangement, more
proper image processing conditions can be set according to the
feature in density which differs from object to object and/or the
purpose of observation, whereby more observable image can be
displayed.
* * * * *